Occurrence of Encephalitozoon cuniculi and Encephalitozoon hellem in European Wild Rabbits (Oryctolagus cuniculus) in Southern Germany (Bavaria)

<i>Encephalitozoon cuniculi</i> and <i>Encephalitozoon hellem</i> are fungus-related, obligate intracellular pathogens belonging to the microsporidia. Both microorganisms occur in mammals, birds and even humans, thus revealing a zoonotic potential. Knowledge of their relevance in wild rabbits is very limited so far. Thus, the aim of the present study was to investigate the occurrence of <i>E. cuniculi</i> and <i>E. hellem</i> in wild rabbit populations in southern Germany (Bavaria). Therefore, blood and organ samples (brain/kidney) of 158 wild rabbits were investigated by immunofluorescence and PCR-based assays. Antibodies to <i>E. cuniculi</i> were detected in 24 of the 158 (15.2%) wild rabbits, while DNA of <i>E. cuniculi</i> was found in 7 (4.4%) and DNA of <i>E. hellem</i> was found in 3 (1.9%). Sequencing identified <i>E. cuniculi</i> genotype 1. This study provides the first <i>E. cuniculi</i> genotype determination in free-living wild rabbits worldwide and the first evidence of <i>E. hellem</i> in rabbits worldwide. Wild rabbits should, therefore, be regarded as a reservoir for both pathogens and, on the basis of molecular evidence from kidney tissue and presumed urine excretion, also as a source of infection for <i>E. cuniculi</i> for animals and humans.